Quality by Design (QbD) Based Optimization and Validation of an RP-HPLC Method for Simultaneous Analysis of Multicomponent Topical Cream

Abstract

This study reports the development and validation of a rapid, specific, and robust Reverse-Phase High-Performance Liquid Chromatography (RP-HPLC) method for the simultaneous estimation of Ofloxacin (OFL), Ornidazole (ORN), Itraconazole (ITR), and Clobetasol (CLO) in a cream formulation. A systematic Quality by Design (QbD) approach, utilizing a three-factor, five-level Central Composite Design (CCD), was employed to optimize chromatographic conditions. The independent variables evaluated were the ratio of the polar phase (water), the pH of the polar phase, and the flow rate, while the response factors included peak tailing and total chromatographic run time.  The optimized chromatographic conditions consisted of a Kinetex® 5µm Biphenyl 10 LC column (250×4.6 mm) with a mobile phase comprising Acetonitrile and Water (pH 4.0 adjusted with orthophosphoric acid) in a 60:40 v/v ratio, a flow rate of 1 mL/min, and a detection wavelength of 249 nm. The method demonstrated excellent linearity (correlation coefficient >0.9990), accuracy (mean recovery between 98.0% and 102.0%), and precision. System suitability parameters, including theoretical plates (>2000) and tailing factors (<2.5), were within acceptable limits. The validated method was successfully applied to the assay of a marketed cream formulation, yielding results consistent with label claims. Robustness studies confirmed the method’s reliability under deliberate variations in flow rate, pH, and mobile phase composition.